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$ \bigcirc$Name

fezw Compress an image with EZW algorithm

$ \bigcirc$Command Synopsis

fezw [-r NLevel] [-e EdgeIR] [-b ImpulseResponse2] [-n FilterNorm] [-w WeightFac] [-d] [-R TargetRate] [-P TargetPSNR] [-s SelectArea] [-o Compress] Image ImpulseResponse [Qimage ]

-r NLevel : Number of level for wavelet tranform

-e EdgeIR : Impulse reponses of edge and preconditionning filters for orthogonal transform (fimage)

-b ImpulseResponse2 : Impulse response of filter 2 for biorthogonal transform (fsignal)

-n FilterNorm : Normalization mode for filter bank

-w WeightFac : Scaling factor for wavelet coefficients

-d : Computes distorsion-rate function

-R TargetRate : Target Rate

-P TargetPSNR : Target PSNR

-s SelectArea : Polygonal regions to be encoded with a different rate or PSNR (Polygons)

-o Compress : Output compressed Image (cimage)

Image : Input image (fimage)

ImpulseResponse : Impulse response of inner filters (fsignal)

Qimage : Output quantized image (fimage)

$ \bigcirc$Function Summary

void fezw (NumRec , Edge_Ri , Ri2 , FilterNorm , WeightFac , DistRate , Rate , PSNR , SelectedArea , Output , Image , Ri , QImage , PtrDRC )

int *NumRec ;

Fimage Edge_Ri ;

Fsignal Ri2 ;

int *FilterNorm ;

float *WeightFac ;

int *DistRate ;

float *Rate ;

float *PSNR ;

Polygons SelectedArea ;

Cimage Output ;

Fimage Image ;

Fsignal Ri ;

Fimage QImage ;

char *PtrDRC ;

$ \bigcirc$Description

This module compresses a floating point image contained in file Image using Shapiro's EZW algorithm [Sha93] applied to its orthogonal/biorthogonal wavelet transform.

A wavelet transform is first applied to the image. If the -b option is selected, then a biorthogonal transform is applied using the filter pair contained in ImpulseResponse and ImpulseResponse2. The edge processing is made by reflecting the image across the edges. If the -b option is not selected, then an orthogonal transform is performed using the filter contained in ImpulseResponse and, if the -e option is selected, the special filters for edge processing contained in EdgeIR (only for Daubechies wavelets). If neither the -e and -b options are selected, then an orthogonal transform is performed with periodization of the image.

The -n option enables to control the filters normalisation. It has the same effect as in owave1 (if an orthogonal transform is performed) or biowave1 (if a biorthogonal transform is performed) modules.

The -r option specifies the number of level of wavelet transform (NLevel must be a positive integer).

After the wavelet transform has been computed, it is compressed with the EZW algorithm [Sha93]. It generates both a compressed representation, which is stored in Compress (if the -o option is selected) and a quantized wavelet transform, which can be reconstructed with the data contained in Compress. A inverse wavelet transform is then applied to the quantized wavelet transform in order to obtain the quantized image which is stored in Qimage (if selected). This is the image which can be reconstructed by applying the decompression module fiezw to Compress.

The -w, -d, -R, -P and -s options have the same effect as in ezw module.

$ \bigcirc$See Also

biowave2, ezw, fmse, ibiowave2, iowave2, owave2.


$ \bigcirc$Version 1.32

Last Modification date : Tue Feb 5 17:44:27 2002

$ \bigcirc$Author

Jean-Pierre D'Ales

next up previous contents index
Next: fiezw Up: Reference Previous: Fezw   Contents   Index
mw 2004-05-05